Mario Kart Papercraft Update

After making a papercraft Light Cycle and giving it to Luigi, it was only natural for me to look for Mario's kart papercraft to make Luigi's bragging rights more evident.
What I found was this one: http://nintendo-papercraft.com/mario-karts/
After trying to get it together, I ran into some problems ranging from obvious to ones that appear only when you try to actually make the model.
The result turned out okay, but while making it I came up with some ideas about how this scheme can be improved. So I decided to update it and make another kart to test it.